Protective device



Dec. 6, 1927. 1,651,872

7E. E. F. CREIGHTON PROTECTIVE DEVICE Filed April 30. 1924 Inventor: V

Elmer-ElF-Tcreicghton v H i s Attofi ney,

Patented Dec. 6, 1927.

UNITED STATES PATENT .OFFICE".

,ELMEB E. F. CREIGHTON, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERALELEC- TRIO COMPANY, A CORPORATION OF NEW YORK. I k v rno'rno'rrvn:nnvron.

Application. filed April 30, 1924. Serial No. 710,146.

' ers, which are employed to divert lightning discharges, surges andother potential phenomena around apparatus which might be injuredthereby, and more particularly to protective devices of the typedisclosed in Letters Patent of the United States to Halsey No. 888,235,dated May 19, 1908.

With arresters of the Halsey type there is a brief interval between theinterruption of the discharge by the volatilization of the liquid andthe restoration its original condition by the return of the liquid tothe tubeduring which the spark voltage of the arresterv is so highthatthe arrester is unable to aiiord the same degree of protection againstthe immediate recur: rence of a high potential discharge that itnormally affords.

According to my invention I connect a plurality of arresters of theabove mentioned type in parallel and modifythe construction of one ormore of them or their connections in the circuit to be protected so thatduring the aforesaid brief interval at which each arrester has its sparkvoltage abnormally high another arrester will be in condition to rovidethe desired protection by reason either of its slower response or itsrecovery from an earlier response. 1 l 3 Another feature of my improvedconstruction comprises the arrangement of electrolyte within themetallic container with the lower end of the tube beneath the level ofthe electrolyte in the container and with an insulating liquid in thespace above the electrolyte to increase the' dielectric strength betweenthe tube and the inner surface of the container.

invention will be better understood from the following description takenin cone 7 and Fig. 2 is a similar nection with the accompanying drawing,and. its scope will be pointed out in the appended claims.

In the drawing Fig. 1 is a diagrammatic representation of one form of myinvention representation of a modification.

Referring first to protected is shown connected to earth by two similararrester units 2 and 3. Each unit of the arrester to of the tube rieswith the two tubes.

Fig. 1, the line 1 to be is represented as comprising the sphere gap 4having a protective cover or rain shield 5,

the sphere gap being connected in' series by conductor 6 with anelectrolytic'member of the type disclosed in the above mentioned Halseypatent. This member comprises the metallic container 8 to the bottom ofwhich is secured the tube 9 of insulating material.

The lower end of the tube 9 is shown closed by a cap 10 extendingthrough which is the electrode 11 by which connection is made to groundthrough the resistance 12. The container is partially filled and thetube is entirely filled with electrolyte 13 which-may be' water as inthe above mention Halsey patent, and within the container L a is shown abafiie plate 14 supported on. a name work 15' also as in that patent;

Various means may be employed for insuring tha't'the two units 2 and 3shall not respond simultaneously to the same high potential impulse andthat the second to respond shall not completely open its discharge pathto ground untilafter the .firstunit torespond shall have operated andagain been restored to its original condition or substantially so. Oneway of effecting this result is to employ two units 2 and 3 havingelectrolytic members of identical form but which have different rates ofex namic energy. This di' erenoe maybrought about asa result of adifference of resistance, for example the electrolyte of one tube mayhave a resistance differingvfr'om" enditure of d that of the other tube,or external resist be used in seg. 1 illustrates the latter expedientwhere" unit 2 is shown having a larger resistance 12 in its groundconnection than unit 3. A second means of obtaining a difference in thetime of action of'the'two units is by using 'tubes .9 ofdifferent sizesfor the two units.

ances of different values miy 1 The same amount of energy expended uponthe different quantities of electrolyte f i will result in a differenceinthe time of the response of the two units. Fig. 1' illustrates thatthe tube 9 of; unit 2 is this means in p thanthe corresponding tubeshown larger 9 of unit 3. 1 in Fig. 1 in addition todiiferentresistances 12 n the ground connections, it is While this means isshownto be understood that these two expedients fneed not necessarily beused together but that either may be used separately-if desired.

the power current following the initial breakdown than unit 2 and as aresult the electrolyte in the tube 9 of unit 3 will'be volatilized or.blown out, thus breaking the are. As soon as the arc is broken, however,electrolyte will be restored in the tube and this will occur before thesmaller proportion of-current through unit 2 will have had time 'tocause this unit to interrupt'its discharge path. The same result wouldfollow were the resistances 12 to be of equal value and were 1 the twounits to differ only in the size of the tubes 9. Unit 3 having. thesmaller tube and i consequently the lessquantity of electrolyte would bethe first to res nd; In the modification illustrated b two similararrester 'units ant? are shown connected in parallel to the line 1.

- Each of the two units comprises a sphere 'timesmt partially with Ielectrolyte 25 tube 27 also of insulating material which contains thesame electrolyte and has a tight vfitting cap 28- through which. extendsthe electrode 29. A resistance 31 connects'the sphere gap with theelectrode 29 and the container 24 is grounded at 32. Above. theelectrolyte 25 is placed a uantity of insulating oil 33 to nearly fill te container, the oil thereby serving to: increase the dielectric ofelectrolyte and the walls of the container.

's'tantiall the same. A heavy current to ground ollowing abreakdown ofthe sphere gaps causes a rapid volatilization and expulsion of theelectrolyte in the tubes 27 whence the circuit isinterrupted. Cooling ofthe volatilizedelectrolyte followin a'n mterruption of the discharpermits 51c electrolyte to return up the'tu As in Fig. 1 the two units20 and 30 are shown provided with resistances -31 of'difierent valuesand the tubes 27 are also shown ofdifiere'nt diameters. Moreover, ifdesired, the electrolyte 1n the two units may be different. By any orall-of these means the two units shown in Fig. 2 may be causedto'respond at different e same manner and for the same purpose as hasalready been .described in connection with the form shown by Fig. 1.

While I have described certain embodiments of my invention, I do notwishto .be

e small- Fig. I 2

Although the arrangement of. parts-is somewhat difiere'nt from that inFig.1, the operation is sublimited to the particular forms shown anddescribed as it will be apparent that many modifications therein may bemade without departing from the scope of my invention as set forth inthe appended claims.-

What I claim as new and desire to se cure by Letters Patent of theUnited States 1s:

'1. A protective system comprising a plurality of units connected toprovide parallel discharge paths, each of said units including meansactuated by a discharge therethrough for interrupting the discharge pathprovided by said unit, said units being constructed to have differenttimes of response when subjected to the same high potential impulse,whereby a subsequent impulse quickly following a first impulse may bedischarged by a unit of slower response.

2. A )rotective system comprising a plurality 0 units conne'ctedtoprovide parallel discharge paths, each of said units includin meansactuated by a discharge therethrougi for interrupting said dischargepath and adapted subsequently to restore said path,

.one of said units being constructed to inter- .fsubsequently to restorethe same before. angap 21 covered by a shield 22 as in Fi 1 and ametallic. container 24 fihed Suspended from the vcover 26' which'is ofinsulating material, is a a discharge therethrough and adapted tointerrupt said discharge path and subsequently to re-establish the same,the characteristics of one of said units being such that theproportionof the discharge traversmg it is in'suflicient to cause it tointerrupt its discharge path until; the discharge path through the otherof said units shall have been interrupted and reestablished.-

4. 'A protective system comprising a unit including a vessel containingan electrolyte and spaced electrodes therein, said vessel 'ha'ving'atubular portion containing one of said electrodes and a similar unitconnected in parallel with said first unit, the resistance of saidsecond unit being less than the resistance of said first unit wherebythe discharge path through saidsecond unit Will be opened and reclosedbefore the discharge path thlOligh said first unit will be opened ofsimilar parallel connected units each including a tube containing anelectrolyte, a pair of electrodes spaced thereby, and a resistance, oneof said resistances being greater than the other whereby when said unitsare simultaneously subjected to a high potential discharge one of theunits will interrupt protective system comprising a pair the dischargepath provided thereby and restore the same before the other of saidunits shall have interrupted the discharge path provided by it.

6. In combination a pair of ii htning arresters connected in multiplewhereby discharges 'may take place through both of said arresters fromthe same line, means in each arrester for breaking the discharge circuitby producing a gap in the dischargecircuit and for restoring thearrester tonormal operative condition after the discharge circuit hasbeen so broken, and for delaying the time of breaking the circuit in onearrester until after the other arrester has been so restored.

7. In combination a pair of lightning ar rosters connected in multiplewhereby discharges may take place through both of said .arresters fromthe same line, means in each arrester for breaking the discharge circuitby producing a gap in the discharge circuit and for restoring thearrester to normal operative condition after .the discharge circuit hasbeen so broken, and for delaying the time of breaking the circuit in onearrester until after the other arrester has beenso restored, saidarresters being of the electrolytic cell type, said means comprising. acolumn of electrolytic material in each arrester, said columns being ofdifierent volume.

8. In combination a pair of lightning arresters connected in multiplewhereby discharges may take place through both of said arresters fromthe same line, means in each arrester for breaking \the dischargecircuit by producing a gap in the discharge circuit and for restoringthe arrester to normal operative condition after the discharge circuithas been so broken, and for delaying the time of breaking the circuit inone arrester until after the other arrester has been so restored, saidarr-esters being of the electrolytic cell type, said means comprising acolumn of electrolytic material in each arrester, said columns being ofdifierent volume, the column in each arrester standing a substantialheight above the level of the electrolyte in the cell and a layer of oilabove the surface of the electrolyte in the cell and surroundingsaid-column. r p v In witness whereof, I have hereunto set my hand this29th day of April 1924.

. ELMER E. F. CREIGHTON.

